[1][2][3] During the Second World War Kielmansegg served in various divisions, staff regiments and fronts in Poland, France and Russia.

Several months later, he was arrested by the Gestapo for being a co-conspirator of the 20 July plot, but released on 23 October 1944 for a lack of evidence.

Remarkably, Fritsch's fierce antisemitism and openly anti-democratic views were not addressed as problematic aspects of his personality.

During this time, he was the German delegate in the negotiations on the European Defence Community and the London and Paris Conferences.

Kielmansegg is considered one of the spiritual fathers of the principle of "Inner Guidance", which was the hallmark of the Federal Armed Forces in uniform with the concept of the citizen.

In 1963 he was again active in the International area and was, since 5 July 1963, as lieutenant general of NATO's Supreme Command, of Allied Land Forces Central Europe in Fontainebleau, in France.

On 15 March 1967, he was promoted to Commander-in-Chief of NATO's forces in Central Europe, first in Fontainebleau, France, and then in Brunssum, in the Netherlands.